1. Technical Field
The present invention relates to a liquid crystal device in which a liquid crystal is held between a pair of substrates, and a projection-type display device which uses the liquid crystal device as a light valve.
2. Related Art
In a liquid crystal device, an element substrate provided with an image display region in which a plurality of pixel electrodes are arranged, at one surface side, and an opposing substrate provided with a common electrode to which a common potential is applied are bonded by a sealing material, and a liquid crystal layer is held within a region surrounded by the sealing material between the element substrate and the opposing substrate. In such a liquid crystal device, when ionic impurities mixed at the time of liquid crystal injection or ionic impurities eluted from sealing materials are agglomerated within an image display region by driving of the liquid crystal device, deterioration of the display quality such as burn-in (spot) of an image is caused. Consequently, a technique is proposed which prevents ionic impurities from being agglomerated within the image display region by providing a peripheral electrode in the outside of the image display region, and attracting and retaining ionic impurities in the peripheral electrode (see JP-A-2008-58497).
Specifically, in FIG. 4 and the like of the technique of JP-A-2008-58497, a first peripheral electrode and a second peripheral electrode are provided so as to surround the periphery of the image display region between the image display region and a horizontal transfer circuit (peripheral circuit portion), and between the image display region and a vertical transfer circuit (peripheral circuit portion). Therefore, when different potentials are applied to the first peripheral electrode and the second peripheral electrode, and the polarities of the potentials applied to the first peripheral electrode and the second peripheral electrode are reversed for each frame, a horizontal electric field is generated between the first peripheral electrode and the second peripheral electrode, and thus ionic impurities are attracted into the first peripheral electrode and the second peripheral electrode, and are retained therein.
However, when the peripheral electrodes (first peripheral electrode and second peripheral electrode) are disposed between the image display region and the horizontal transfer circuit (peripheral circuit portion), and between the image display region and the vertical transfer circuit (peripheral circuit portion) so as to surround the periphery of the image display region, there is a problem that when an alternating current is applied to the peripheral electrodes, the signal is distorted and the display quality is deteriorated due to coupling between the data line and the peripheral electrodes, or coupling between the scanning line and the peripheral electrodes.